Wrinkling of {alpha}-alumina films grown by oxidation. 2: Oxide separation and failure

Journal Article · Tue Sep 01 04:00:00 EDT 1998 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(98)00134-7· OSTI ID:669806

Tolpygo, V K; Clarke, D R ^[1]

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1. Univ. of California, Santa Barbara, CA (United States)

Two types of localized separation of the {alpha}-Al{sub 2}O{sub 3} scale, grown on a Fe-Cr-Al alloy at 1000 C, occur after isothermal oxidation and cooling to room temperature. One type is a form of buckling where the size of the detached region is much larger than the thickness of the oxide and is usually accompanied by substantial stress relaxation and cracking of the scale. It is observed within a narrow range of oxide thickness of about 0.2--0.5 {micro}m. The second type is intimately related to the wrinkling morphology of the scale and takes place primarily along the ridges of the longer wavelength wrinkles. No significant stress relaxation in the oxide appears to accompany this form of separation unless cracking of the scale occurs as well. The consequences of thermal cycling on these modes of separation and how they may lead to oxide spalling are discussed.

• OSTI ID: 669806
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 14 Vol. 46; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
ALUMINIUM OXIDES
CHROMIUM ALLOYS
CRACKS
FRACTURE PROPERTIES
IRON ALLOYS
OXIDATION
STRESSES
THIN FILMS